Keystones — Lintel
Five GCSE retrieval questions · 29 January 2026 · mathsvault.uk/keystones
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1. Number Error intervals
A value is 18.9 (to dp). State the error interval
Answer: 18.85 ≤ x < 18.95 -
2. Algebra Expanding two brackets
Expand: (x - 5)(x - 6)
Answer: x² - 11x + 30 -
3. Geometry Area of a circle
Calculate the area of a circle with diameter 11cm
Answer: 95.03cm² -
4. Ratio One amount as a percentage of another
47 out of 91 students passed. What percentage passed?
Answer: 51.6% -
5. Statistics Averages and range
Find the mean, median and range of: 70, 40, 87, 14, 60, 72, 22, 72, 27
Answer: Mean = 51.6, Median = 60, Range = 73